Linear voltage generator



April 25, 1950 J. w. PlcKlNG 2,505,688

' LINEAR VOLTAGE GENERATOR Filed July 24, 1946 LAALWE' M wma PatentedApr. 25, 1950 umn-:Dl omet LINEAR-YOLNEEATQR.,

.TayW-.Picking, Cleveland, Q-hioi, assignonztoi'lhe.

' Reliance; Electric/ai Engineering company-,.-

hnilicatimi,Julyt 24, 1946,A (Camro- 21 Claims. l.

My invention relatesyin` general tov electrical; circuits to provide aconstant current or afvolt-v agre; which will increase-and decrease.;linearly.

An object. of my invention is` an Veleei', ric al- -cir,-` cuit toprovide a constant current or a voltage which will increase and decreaselinear-ly ata; definite predetcrminable adjustable rate ton,- any.predeterminable adjustable value.

Another object of. my invention is anlelectrical': circuit which willprovide. a constant current.- or. aj voltage which willwincrease at anessentially linear rate to` any predeterminable adjustable value.

Another object ofv my invention isan electrical-y circuit to provideaconstant current or a voltage, which will decrease at anessentiallylinearrate tol any predeterminable adjustable, value',

Other objectsand-a fuller understanding of, my invention maybehad-,byreferringto the following description and claims,`taken. inconiunction v'vith the accompanying drawing, inI which:

Figure 1 shows the preferred forni oi my inventionwh'erein thei linearlyvariable voltage ap*-` pears across the points A and B, which i`s beingapplied to anelectrically controllable device; and

Figure k2 showsamodied form of my. invention, wherein; the linearlyvariable voltage appears; across ther electrical device, at terminals6L2`Jand Gli-L.

In Various ,controlV schemes itis; common practice to use thecombination of' a condenseianda resistorto provide a voltage which can,be` used' to increase or decrease.inv a predetermined tima However, therate is not linear. The,` change ofi voltagerwith respectto time forthistype of cir.v cuit is an exponentialY function.V InQmany cases it isdesirable tohave the rate of voltage change linear and constant. Apentode thermioni'ctube hasirequently been used as thevryesistor in are.. sistor-condenser combination. The constant current characteristicof this type of' tube mcdiiries the, exponential' characteristic to onewhich is es-4 sentially linear. A disadvantage ofY this system; is thatthe thermionic tube can passv current in one direction. only andvtherefore the voltage across the condenser can bel causedto rise, butitk cannotbe reduced through the samecircuit. My invention makes useofthe combination, of'zairco'ndenserV and a pentode thermicni'ci tube;and pijovides for both charging .and discharginev the con-y denserbyadding toftlfie combination abridge rectier so thatcurrent'can flowto'andcfrom therk condenser but l pass through .thepentodethermifonicftub'e in one direction,only;V In, reference tov liefure4 l,my invention comprises afbiildge. .rectife, 12,-.; fiat/ieg( ifilut @ne'OutputtemeelS-Q a- .2i thermionicpentod'e tube I. l across-,the outputterminals ofrthe bridge rectifier l2, aV condenser lf3,- and:y akunidirectionali-source of current'` IIT-the condenser. fit1-audthe.unidirectionali7 source'V -oi current |14 :being disposed in seriescircuit relation-ship across thelinput .tciminals of -thebridgerectifierv |12; electrically-i.controllable device 56is shoivnconnectedacross` the 'terminals A and:` Bof `the condenser. |531' More.specically; `thebridge rectifier has arst. input. termi-nal- 5,- and:` aseconinputlterminal Bg-,andianrSt output .terminal [1fand a-secon-d:output: terminal |28.. The; bridge recti'iierihas iirst, second, third:ands fourthunid-inectionalfU current;y passing; devices.. Ywith'.referencezvrmmbersl; 2li-,inzit imrespectively,w In: thisJ .descriptiomcurreniiwilli be assumed to vflow in the-direction ofgtheieliectronrnew., Therst unidirectionalecurrent; passingdevice I9 is. connectedto'.` passi electron current from the: rst oi-itpu-t;,terminalIa'lptoi'the-/rsti-,inputIterminal |152; the secoxrdyunidirectionalcurrent passing device 20; is connected toi-.passelectron current -frornthe first-output termina-ttl; :tothasecond iiiputtermii.-A nai, |65;ythe; thirdp unidirectionalev current passing. devic.e 2|: is:Vconnected; ta pass.; electronf current` from,thezrst-irieutfterminal itcthe; secondi out:-` put terminal I8; and the fourth unidirectionalf`currentpsingidvice: 2:2;'S- G0l1113c-t1'1d` to Dass electronl currentvfrom the-second inputr terminal met@ the.; second outputterrninal 8^.lThethermanode 12;3;A a contratgridy 21,; a screen grid; 26;-r and:`aiSuppressQn-erdrli 'I'heamdefof thethermlionic. pentQde/tub -Ic|fiss-connected to the rst out-- mitA terminal IJ- of y the4 bridge.Vrectifier |2, and the-.cathode Napf thesthermionic nentody tubeI-lis;coririecljiedIr tothe. second; output terminal l 8:ofithebridgerectiiier |23.A AD. C;supplysource-,Ztlv suppl' Jdirectycurrentl potential; to the screen.- g-ridgZ o f -thecontrol grid- 2-'l--of the thermionic pentodegtubegilvji ThefD; Qtr-.supply source-28g-hals: a -Pesitive terminal; 29 andianeeative terminal- 3U..Qeneectedv across; weee: terminals 0i-the D= supply-seance 21B-111syaser-een and poten-Gialresister 3|,t a,, controli grid ipotentiallimiting l resistor A32;- andeazcontrol grid-', potentionieten335m series., A; ennectin 3,41 connects. the?, positive endv 0f thescreen-feria; potential resistor-,3L to the positivetetminelflfof the1?- Supplye Sourf 'MtV Ay L 3,;5 connects the negative endo f the 32.The negative end of the control grid potentiometer 33 is connected tothe negative terminal 30 of the D. C. supply source 28. The screen gridpotential which appears at the positive terminal 29 of the D. C. supplysource 28 and at the connection 34 is applied to the screen 26 of thethermionic pentode tube II through the current limiting resistor 31. Thecathode 24 of the thermionic pentode tube II is connected throughconductor 39 to the connection 35 between the resistors 3| and 32, toprovide the reference voltage for the cathode. The control grid 21 isconnected through conductor 48 to the movable linger 38 on thepotentiometer 33, to provide a variable negative voltage on the controlgrid 21 with respect to the cathode 24 of the thermionic pentode tubeII. The control gri-:l potential limiting resistor 32 prevents thenegative potential of the control grid 21 with respect to the cathode 24from becoming too small a value. The suppressor grid 25 is connectedthrough a conductor 4I to the cathode 24.

The condenser I3 has a iirst terminal A and a second terminal B. Thesecond terminal B is connected to the rst input terminal I of the bridgerectiiier I2. The unidirectional source of current I4 has a negativeterminal 44 and a positive terminal 45. The iirst terminal A of thecondenser I3 is connected to the negative terminal 44 of theunidirectional source of current I4 through a conductor 46. Apotentiometer 41 is connected across the terminals 44 and 45 of theunidirectional source of current I4. A single pole double throw switch49 is connected to either include or exclude the unidirectional sourceof current I4 from the series circuit arrangement and has a rstconnection 58, a second connection 5I, a common connection 52 and acontact member 53. A movable finger 48 of the potentiometer 41 isconnected to the second connection 5I of the switch 49. A conductor 54connects the negative terminal 44 of the unidirectional source ofcurrent I4 and the first connection 5I] of the switch 49. A conductor 55connects the common connection 52 of the switch 49 and the second inputterminal I6 of the bridge rectifier I2.

In practice, the circuit operation will start When the switch is thrownso the contact member 53 connects the second connection 5I to the commonconnection 52 of the switch 49. The potential of the unidirectionalsource 4oi current I4 will cause electron current to iiow from thenegative terminal 44 through conductor 46 to the iirst terminal A ofcondenser I3, through the condenser I3 to the second terminal B thereof,then to the first input terminal I5 of the bridge rectier I2, throughthe third unidirectional current passing device 2l to the second outputterminal I 8, then to the cathode 24 and the anode 23 of the thermionicpentode tube II, then to the first output terminal I1, through thesecond unidirectional current passing device to the second inputterminal I6 of the bridge rectifier I2,

through the conductor 55, the common connecrise, and this rising voltagewill be in opposition to the voltage of the unidirectional source ofcurrent I4, which will lower the potential applied across the anode andcathode of the thermionic pentode tube I I. The voltage across thecondenser I3 will continue to rise and the voltage across the tube I Iwill continue to decrease until the condenser I3 has been charged to apotential equal to the potential setting of the potentiometer 41. Thispotential setting can be varied by the movable iinger 48 from any valuefrom zero up to the maximum potential of the unidirectional source ofcurrent I4. The signal voltage which this electrical circuit produceswill appear across the terminals A and B of the condenser I3, andtherefore this signal voltage may be adjusted to any predetermined valueby adjusting the movable finger 48 of the potentiometer 41.

A characteristic of a pentode thermionic tube is that it will conductessentially constant current regardless of the potential impressedbetween the anode and the cathode of the tube. In this circuit, thevoltage impressed between the anode and the cathode of the tube variesfrom the maximum setting of the movable iinger 48 of the potentiometer41 at the start of the cycle of operation to a zero potential at the endof this cycle of operation, which potential change is the inverse ofthat potential appearing across the terminals A and B of the condenserI3. Because of this essentially constant current conductingcharacteristic of the therrnionic pentode tube, the condenser I3 will becharged at an essentially linear rate to the predeterminable adjustablevalue.

The rate at which the thermionic pentode tube will pass current isregulatable by the setting of the movable finger 38 oi the potentiometer33, which varies the negative potential of the control grid 21 Withrespect to the cathode 24. As the movable finger 38 is moved toward theconnection 3G, the potential of the control grid 21 is made lessnegative with respect to the cathode 24, and therefore the tube II willpass a greateramount of current. Conversely, as the control grid 21 ismade more negative with respect to the cathode 24 by moving the movablefinger 38 closer to the negative termnal 3U of the D. C. sup ply source28, the tube II will conduct less current. This function allows the timerate at which the condenser I3 is to be charged to its predeterminedsetting to be adjusted at will, which means that changing the positionof the movable finger 38 varies the slope of the time versus voltagecurve for this cycle of operation of this electrical circuit.

Now, when the contact member 53 of the switch 49 connects the firstconnection 50 to the common connection 52 of the switch 4S, theunidirectional source of current I4 is excluded from the circuit, andthe condenser I3 will start to discharge through the bridge circuit andpentode thermionic tube I I, In this case, the electron or current iiowis from the iirst terminal A of the condenser I3 which will be thenegative terminal, then through the conductor 46 and 54 to the firstconnection 5U, the contact member 53 and the common connection l52 ofthe switch 49, through the conductor 55 to the second input terminal I6of the bridge rectiiier I2, then through the fourth unidirectionalcurrent passing device 22 to the second output terminal I8 of the bridgerectifier I2, then through the cathode 24 and anode 23 of the thermionicpentode tube II to the iirst output terminal i1 of the bridge rectifierI2, then through. the first unidirectionalY current passing device L91.to theiirst input.-terminal. If of the bridge rectiiier..` -I Land.thencereturn.. to: the Y see-y ond or positive terminaly Bl of` the.condenserV Iii. Thethermionicpentode tubeV I-Iy actsinthe. same mannerasitdidduringfthe chargingof. thecondenser I.3,.in that.it-passesaconstant current. As hereinbefore ncted-,. the rate.. atwhich. the thermionicpentode tube I:I willA pass current is determinedby the setting. ofv themovable finger 38 onthepotentiometer 33. Thissetting again sc-:rvesthe:r function of` determining, the time rate of.discharge of the. condenser I'3. the condenser I3 discharges, thepotential impressed across the. anode and. cathode. of.v the thermionicpentode II .Willzdecrease as.a..function.l of the time. However, thisdecrease. in.. the. applied potential across the.. anode and. cathodeoil the. tube III Will not materially vary. the rate of current"conducting of the tube due. to the.` characteristic o'flthe pen.- todethermonic. tube.

This electrical circuit, therefore, vwill: then.v provide a.vol-tagesignalwhich appearsvat the terminals A.and B of. theLcondensei-I3`whichV will increaselinearly at a d'enite. predeterminable adjustablerate to any predeterminable adjustable value, and decrease linearly at adeiinite predeterminable. adjustable.. rate. to any prede termLnable.adjustable value'. An electrically con trollable device 56. isshownyconnected. across the terminalsA and B of thecondenser B'f to utilizethe voltage.

In Figure 2,.the bridge rectifier. I2 is iden-tical Withthe. bridgerectier I2' in Figures 1. and 2. Across theV output terminals IT and I8of the bridge: rectifier I2v is connected ay unidirectional constantcurrent passing. device 60,having an input terminal 58 and an output.terminal"y 591 The input` terminal 58 and the output. terminal 59-areAconnected to the output. terminals IB" and I1 respectively of. the.bridge rectifier. I2; The devicev I3!) therefore passes. current.fromthe second output terminal I 8- to the iirstoutput terminal. II'.The unidirectional constant current passingr device |50` may be anelectronic tube or' any other electrical device possessing. thischaracteri'stic. An electricaljdevice 61| ha'Ving-aiirst terminal 62 andasecond terminal`63 has the second terminal G3i connected tothe,iirstinput terminal. I5. of the bridge. rectifier I2, and the iirstterminal 62 connected through. conductor 46 to the negative terminal 44of the unidirectional source .of currentA I4. The unidirectionalvsource. of current I4, having. a negative terminal 44 and a positiveterminal 45,.is identicalwith the unidirectional source of current4 I4`in Figures 1 and .2. Switch means` or connection means G4 are providedto connect the. conductor '55V either to the positive terminal`45`or thenegative terminal 44.0f the unidirectional source of current I4. Theoperation ofthis circuit'is the 'same as for Figure 1. Passage of"current throughthe electrical device 6I will cause avoltage drop acrossthis electrical device 6I in proportion to thelimpedance thereof. Anelectricallyfcontroll'abledevice 56 may be connected in parallel.`acrossthe` terminals 6'2 and`63 of the electrical device 6I;

asshown in Figure l', inorder to use the signal' voltage developed.acrossv the terminals' 62 and 63 of the electrical'device 6I. Theelectrical 'device 6I may be an electrical energy storing devicaiorYwhich. case the connection means. 64`is provided. to .exclude ,the-.unidirectional..source .of .current I .4.V

from. theseries. circuit arrangement, incwhicl'i` case the. electricalenerg-v storing.. device will-rev 6 lease its stored energythroughthebridge rectie erl I2 tothe unidirectional constant current passingdevice'` 60 connected across the output terminals ofthebridgerectier I2.This :passage of currentfwould be analogousv tothe=passageof` currentfrom the discharge-of thefoondenser` in Figure l, and would-v result inanessentiallylinear voltage change across,k the electrical device 6I,dueto the constant-current iiowinginl the circuit;

The electrical device 6 I Y may also be any" device that utilizesalconstantcurrent-regardless of'vvariations inthe applied. potential,rather Vthan lusing the voltage Adeveloped across'. the Ielectricaldevice tobeapplied toan electrically controllablev device..

Any rate of changein thesettingof `thefpotentiometer 41 in'excessofthe-rate of-voltage-change allowed across the condenserzr I3,`byAthe-settingeofi the potentiometer 33, Will act the samefas throw ingthe switch. 49.

AlthoughY I have described by invention in its preferred form witha-'certaimdegreeoff particu.- larity, it is understoodthat thepresentfdisclo.- sure of the preferred formhas been made only. byway ofexample and `that numerouschanges in the details of construction. andthev combination and arrangement ofparts` may be resorted to Withoutdeparting from'y the spirit and the scope ofl the invention ashereinafter claimed.V

I claim:

l. An electrical circuit for supplying a' voltage comprising,in'combination; a ybridge Arectifier having` t-Woinput and two outputterminals,YV thermionic tubehaving atleast two elements,zthe saidA twoelements being conne'ctedacross the said output'terxninals or the said.bridge rectiiiena condenser, a'unidirectiona'lsourceof current, andelectrical connection meansior connecting.' the said unidirectionalsource ci cLirren-t and Tthe said condenser' in series" circuitiarrangement' with the said inputtermi-nals 'of theA saidfbridgerectifier.

2r An electrical circuit for supplyingifa voltage comprising, incombination, a bridge. rectifier having two input and-two outputterminals;` a thermionic tube having. atleast two elements,- the saidtwo elements being connectedfacrossvth'e sad output Iterminals of the.saidibridge"rectiiier, a condenser, aunidirectional scurceoi current;first disengageable electricalfconnection means for connecting-the saidunidirectional source-oi cur.-u rent andthe said condenserin series=circuit ar rangement with the said input terminalsvoff the said bridgerectifierY and: second disengageable electrical connection means'Y for'connectingl the said condenser' in series circuit-arrangement with thesaid input-terminalsof the said bridge recti Iier.

3. Anfelectrical circuitcomprising,l inccmbina` tion, a'bridge rectifierhaving two finput and two-V output terminals, ar thermionic tubeA havingan anode and al cathode,1said anodeandsaidcathodebeing connected acrossthev said output ter,- minalsl. of the said bridgefrectiiier,r acondenser', a variable unidirectionaly source o-fcurrent, firstdisengageableelectrical connectionv means for connectng the saidvariable unid-.irectionalsource of current and thefsaidfcondenserinseries circuit arrangement with the said input terminals ofi thesaidbridge rectier to-c-hange'the said-=con'- denser toany adjustable'value. and. second dien engageabl'e electricalconnection means-forconnectng the.- said condenser'inz-seriesfcircuit arrangement with thesaid-inputterminals Iof the said bridge rectifier'. to. rdischarge; thesaidcon.- denser.

4: electricalcircuit =comprising,1 in. combinau tion, a bridge rectifierhaving first and second input terminals and first and second outputterminals, a thermionic tube having at least; an anode and a cathode, anelectrical energy storage device, a unidirectional source of current,first connection means for connecting the said anode and the saidcathode of the said thermionic tube to the first and second outputterminals respectively of the said bridge rectiiier, first disengageableelectrical connection means for connecting in series circuit arrangementthe said input terminals of the said bridge rectier, the said electricalenergy storage device, and the said unidirectional source of current,and second disengageable electrical connection means for connecting inseries circuit arrangement the said input terminals of the said bridgerectifier and the said electrical energy storage device.

5. An electrical circuit comprising, in combination, a bridge rectifierhaving two input and twooutput terminals, a unidirectional constantcurrent passing device connected between the two output terminals of thebridge rectifier, an electrical energy storage device, a unidirectionalsource of current, and electrical connection means for connecting thesaid input terminals of the said bridge rectier in series circuitrelationship with the said unidirectional source of current and the saidelectrical energy storage device.

6. An electrical circuit comprising, in combination, a bridge rectifierhaving two input and two output terminals, a unidirectional constantcurrent passing device connected between the two output terminals of thebridge rectifier, an electrical energy storage device, a unidirectionalsource of current, rst disengageable electrical connection means forconnecting the said input terminals of the said bridge rectiiier inseries circuit relationship with the said unidirectional source ofcurrent and the said electrical energy storage device, and seconddisengageable electrical connection means for connecting the said inputterminals of the said bridge rectifier in series circuit relationshipwith the said electrical energy storage device.

7. An electrical circuit comprising, in combination, a bridge rectiei`having rst and second input and rst and second output connections, saidbridge rectifier having rst, second, third and fourth unidirectionalcurrent passing devices, first connection means for connecting the saidfirst unidirection current passing device between the first outputconnection and the rst input connection to pass current from the formerto the latter, second connection means for connecting the said secondunidirectional current passing device between the first outputconnection and the second input connection to pass current from theformer to the latter, third connection means for connecting the saidthird unidirectional current passing device between the first inputconnection and the second output connection to pass current from theformer to the latter, fourth connection means for connecting the fourthunidirectional current passing device between the second inputconnection and the second output connection to pass current from theformer to the latter, a thermionic tube having a cathode, an anode, acontrol grid, and an essentially constant current conductingcharacteristic despite varying anode-cathode potentials, the saidcathode being connected to the said second output connection of the saidbridge rectifier, and the said anode being connected to the said firstoutput connection of the said bridge rectier, variable D. C. supplysource for biasing the said control grid With respect to the saidcathode, an electrical energy storage device, a variable unidirectionalsource of current having a first and a second terminal, firstdisengageable connection means for connecting the said input terminalsof the said bridge rectifier in series circuit arrangement with the saidvariable unidirectional source of current and the said electrical energystorage device, and second disengageable connection means for connectingthe said input terminals of the said bridge rectifier in series circuitarrangement with the said electrical energy storage device.

8. An electrical circuit for supplying an essentially linearlypredeterminably variable voltage to an electrically controllable device,said electrical circuit comprising, in combination, a bridge rectiiierhaving two input and two output terminals, a thermionic tube having ananode, cathode and a control grid and having an essentially constantcurrent conducting characteristic despite variations in the potentialdifference between the anode and the cathode, the said anode and thesaid cathode of the said thermionic tube being connected across the saidoutput terminals of the said bridge rectier, predeterminably adjustablebiasing means for varying the potential difference between the saidcathode and the said control grid, an electrical energy storing device,a unidirectional variable source of current, first disengageableelectrical connection means for connecting the said unidirectionalvariable source of current in series circuit arrangement with the saidelectrical energy storing device and the said input terminals of thesaid bridge rectifier to store electrical energy in the said electricalenergy storing device at a predeterminable adjustable essentially linearrate to a predeterminable adiustable value, and second disengageableelectrical connection means for connecting the said electrical energystoring device in series circuit arrangement with the said inputterminals of the said bridge rectifier to release the stored electricalenergy in the said electrical energy storing device at a predeterminableadjustable essentially linear rate, the said electrically controllabledevice being connected in parallel circuit arrangement with the saidelectrical energy storing device.

9. An electrical circuit for supplying an essentially constant currentto an electrical device, said electrical circuit comprising, incombination, a bridge rectier having two input and two output terminals,a unidirectional constant current passing device connected between thetwo output terminals of the bridge rectier, a unidirectional source ofcurrent, and electrical connection means for connecting the saidelectrical device in series circuit arrangement with the two inputterminals of the said bridge rectiiier and the said unidirectionalsource of current.

10. An electrical circuit for supplying an essentially linearly variablevoltage across two output terminals thereof, said electrical circuitcornprising, in combination, a unidirectional variable source ofcurrent, a bridge rectifier having two input and two output terminals, athermionic tube having an anode, a cathode, a control grid, a screengrid, and a suppressor grid, the said anode and the said cathode of thesaid thermionic tube being connected across the said two outputterminals of the said bridge rectifier, an electrical energy storingdevice, a D. C. supply source having a positive, a negative and anintermediate terminal, first connection means for connecting thepositive terminal of the said D. C. supply source to the said screengrid of the said thermionic tube, second connection means for connectingthe said negative terminal of the said D. C. supply source to thecontrol grid of the said thermionic tube, third connection means forconnecting the said intermediate terminal of the said D. C. supplysource to the said cathode of the said thermionic tube, adjustablebiasing means for varying the potential difference between the saidcathode and the said control grid, fourth connection means forconnecting the said suppressor grid to the said cathode of the saidthermionic tube, first disengageable connection means for connecting thesaid unidirectional variable source of current in series circuitarrangement with the said electrical energy storing device and the saidinput terminals of the said bridge rectier and second disengageableconnection means for connecting the said electrical energy storingdevice in series circuit relationship with the said input terminals ofthe said bridge rectifier, the said output terminals of the saidessentially linearly variable voltage generating circuit being acrossthe said electrical energy storing device.

l1. An electrical circuit comprising, an electrical energy storagedevice, a substantially constant current passing device, a substantiallyundirectional impedance, and electrical connection means for connectingthe aforesaid elements in series for discharging the stored energy insaid electrical energy storage device at a substantially constant rate.

12. An electrical circuit comprising, an electrical device, a source ofvoltage, a substantially constant current passing device, unidirectionalcurrent passing means, and electrical connection means for connectingthe aforesaid elements in series for conducting current to saidelectrical device at a substantially constant rate.

13. An electrical circuit comprising, an electrical energy storingdevice, a source of unidirectional voltage, a substantially constantcurrent passing device, iirst unidirectional current passing means,electrical connection means for connecting the aforesaid elements inseries for storing energy in said electrical energy storing device at asubstantially constant rate, second unidirectional current passingmeans, and electrical connection means for connecting in series saidelectrical energy storing device, said substantially constant currentpassing device and said second unidirectional current passing means torelease the stored energy in said electrical energy storing device at asubstantially constant rate.

14. An electrical circuit comprising, an electrical energy storingdevice, a source of unidirectional voltage, a substantially constantcurrent passing device, unidirectional current passing means, electricalconnection means including switch means for selectively connecting theaforesaid elements in Series for storing energy in said electricalenergy storing device at a substantially constant rate and forselectively excluding said source of unidirectional voltage in saidseries circuit.

15. An electrical circuit including a condenser, a source of voltage,rectifier means, a pentode thermionic tube, and connection means forconnecting the aforesaid elements in series relationship to charge thecondenser at a substantially uniform rate.

16. An electrical circuit including a condenser, a source of voltage,rectifier means, a pentode vf10 thermionic tube, connection means forconnecting the aforesaid elements in series relationship to charge thecondenser at a substantially uniform rate, and switch means in saidconnection means operable to selectively exclude said voltage sourcefrom said series relationship.

17. An electrical circuit comprising, an electrical energy storagedevice, a network having four arms and having iirst and secondterminals, and means for connecting said network terminals in serieswith said energy storage device, said network including unidirectionalcurrent passing means and substantially constant current passing means,said aforementioned series connection providing a path for currentthrough at least a part of said unidirectional current passing means andat least a part of said substantially constant current passing means torelease energy stored in said energy storage device.

18. An electrical circuit comprising, an electrical energy storagedevice, a voltage source, a network having four arms and having firstand second terminals, and means for connecting said network terminals inseries with said energy storage device and said voltage source, saidnetwork including unidirectional current passing means and substantiallyconstant current passing means, Said aforementioned series connectionproviding a path for current through at least a part of saidunidirectional current passing means and at least a part of saidsubstantially constant current passing means to store energy in saidelectrical energy storage device.

19. An electrical circuit comprising, an electrical energy storagedevice, a voltage source, a network having four arms and having firstand second terminals, and means including switch means for connectingsaid network terminals in series with said energy storage device andsaid voltage source, said network including unidirectional currentpassing means and substantially constant current passing means, saidaforementioned series connection providing a path for current through atleast a part of said unidirectional current passing means and at least apart of said substantially constant current passing means to storeenergy in said electrical energy storage device, and said switch meansbeing operable for excluding said voltage source from said seriesconnection to release the stored energy in said energy storage devicethrough at least a part of said unidirectional current passing means andat least a part of said substantially constant current passing means.

20. An electrical circuit comprising, an electrical energy storagedevice, a voltage source, a network having two different paths betweeninput terminals, and means including switch means for connecting saidinput terminals in series with said electrical energy storage device andsaid voltage source, said network including unidirectional currentpassing means and substantially constant current passing means in atleast one of said paths for passing current between said input terminalsto store energy in said energy storage device, and said switch meansbeing operable for excluding said voltage source from said seriesconnection to release the energy stored in said energy storage devicethrough said network.

21. An electrical circuit comprisign, a condenser, a unidirectionalvoltage source, a fourterminal network having first and second pairs ofterminals, and means including switch means for connecting said firstpair of network terminals in series with said condenser and said voltagesource, said network including reetiner means' and thermionic pentodemeans for passing current between said first pair of terminals andthrough at least one of said second pair of ter minals to charge saidcondenser, and said switch means being operable for excluding saidvoltage source from said series connection to discharge said condenserthrough said network.

JAY W. PICKING.

The fol REFERENCES CITED lowing references are of record in the file ofthis patent:

Number UNITED STATES PATENTS Certificate of Correction Patent No.2,505,688 April 25, 1950 JAY W. PICKING It is hereby certified thaterrors appear in the printed specification of the above numbered patentrequiring correction as follows:

Column 6, line 68, for the Word change read charge; column 7, line 52,for unidireotion read unidirectional; column 10, line 70, for comprisignread comprz'svlng; and that the said Letters Patent should be reed Withthese corrections therein that the same may conform to the record of thecase in the Patent Office.

Signed and sealed this 11th day of July, A. D. 1950.

THOMAS F. MURPHY,

Assistant Gommzssz'oner of Patents.

Certificate of Correction Patent N o. 2,505,688 April 25, 1950 JAY W.PICKING It is hereby certied that errors'appear in the printedspecication of the above numbered patent requiring correction asfollows:

Column 6, line 68, for the Word change read charge; column 7, line 52,for

unidireetion reed unidirectional; column 10, line 70, for comprsigu readcom.

prising; and that the said Letters Patent should be read with thesecorrections therein that the same may conform to the record of the casein the Patent Ofloe.

Signed and sealed this 11th doy of July, A. D. 1950.

[sun] THOMAS F. MURPHY,

Assistant 'ommz'sszoner of Patents.

Certificate of Correction Patent N o. 2,505,688 April 25, 1950 JAY W.PICKING It is hereby certified that errors appear in the printedspecification of the above numbered patent requiring correction asfollows:

Column 6, line 68, for the Word change read charge; column 7, line 52,for unidirection read unidirectional; column l0, line 70, for comprisignread compricing and that the said Letters Patent should be reed Withthese corrections therein that the same may conform to the record of thecase in the Patent Office.

Signed and sealed this 11th dey of July, A. D. 1950.

[SEAL] THOMAS F. MURPHY,

Assistant 'ommz'asz'oner of Patents.

